Acetylated pustulanes

Nishikawa Y, Tanaka M, Shibata S, Fukuoka F (1970) Polysaccharides of lichens and fungi. IV. Antitumor active 0-acetylated pustulan-type glucans from the lichens of Umbilicaria species. Chem Pharm Bull 18 1431-1434... 

Table I describes the glucans we examined, including their source, molecular weight, and solubility in H20 The samples were used without further purification, with the exception of pustulan i9)y which was purchased as an unbleached and partially acetylated extract of the lichen P. papullosa. Deacetylation (saponification) of native pustulan was accomplished by dissolving the material in 1% aqueous NaOH at 90 C and allowing the solution to stand at 50-60 C overnight. Following neutralization with HCl, the brown colored solution was bleached with NaClO yielding a faintly yellow solution. The bleached pustulan was precipitated with 95% ethanol and collected by vacuum filtration. After several washings with alcohol, the precipitate was redissolved in hot water, allowed to cool, and dialyzed using an Amicon ultrafiltration membrane apparatus. Solutions were then freeze dried.

---